1. Field of the Invention
The present invention relates to a semiconductor device of the type “system in package” (SIP) having a stack structure in which a plurality of semiconductor chips are sealed into a module substrate.
2. Description of the Background Art
When a stack of a plurality of semiconductor chips are sealed into a module substrate, the electrode pad of a lower semiconductor chip overlaps with the upper semiconductor chip, and wire bonding cannot be performed, so it is possible to make a spacer intervene between the semiconductor chips to secure a space between them which lets a wire pass. In Japanese Unexamined Patent Publication No. 2005-322767, when the electrode pad of a lower semiconductor chip overlaps with the upper semiconductor chip, the spacer of both intermediate sizes is made to intervene between both sides, and a plurality of through holes or level differences are formed in the central part of the spacer according to the position of the electrode pad of a lower semiconductor chip. This enables the wire connected to the electrode pad of a lower semiconductor chip to be arranged without contacting the upper semiconductor chip. The main point of Japanese Unexamined Patent Publication No. 2005-322767 is to enable the wire connected to the electrode pad of a lower semiconductor chip which overlaps with the upper semiconductor chip to be arranged without contacting the upper semiconductor chip.